module 2: electronic configuration Flashcards
what are the rules for assigning oxidation numbers
- O is +2 with F
- O is -1 in a peroxide
- H is -1 with metals
- aluminium = +3 always
- g1 = +1 always
- g2 = +2 always
what is an acid
a species that is a proton donor
what is a base
a species that is a proton acceptor
what is an alkali
a water soluble base
what is a strong acid
an acid that fully dissociates into a solution of H+ ions
what is disproportionation
when one element in a reaction is both oxidised and reduced
in a redox reaction between an acid and a metal what is oxidised/reduced
metal is oxidised => positive metal ion
hydrogen from acid is reduced => hydrogen as an element
acid + metal –>
acid + metal –> metal salt + hydrogen
acid + alkali –>
acid + alkali –> metal salt + water
acid + metal oxide –>
acid + metal oxide –> metal salt + water
acid + metal hydroxide –>
acid + metal hydroxide –> metal salt + water
acid + metal carbonate –>
acid + metal carbonate –> metal salt + water + carbon dioxide
what is an oxidation number
a measure of the number of electrons that an atom uses to bond with the atoms of another element
what does a reduction/increase in oxidation state mean
reduction in os = species was reduced
increase in os = species was oxidised
what are the 2 disproportionation reactions that you need to know?
Cl2(aq) + H2O –> HClO(aq) + HCl(aq)
chlorine is added to water to kill bacteria to make water safe to drink, hydrochloric and chloric acid are formed
Cl2(aq) + 2NaOH(aq) –> NaCl(aq) + NaClO(aq) + H2O(l)
bleach is formed when cold, dilute, aqueous sodium hydroxide and chlorine react at room temperature
what is first ionisation energy
the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ atoms
what are the 3 factors that affect ionisation energy
- nuclear charge
- distance from nucelus
- electron shielding
how does ionisation energy change as you go down group 2
it decreases
the number of filled shells increases as you go down a group
so shielding and distance from nucleus increases, making it easier to remove the outermost electron
what is an orbital
a region within an atom that can hold up to two electrons, with opposite spin
outline an s orbital
its spherical
each shell will contain an s orbital
the greater value of n, the greater the s-orbital radius
outline p-orbitals
3D dumb-bell shape
from the 2nd shell onwards, each shell contains 3 p-orbitals
the greater the value of n, the further the p-orbital from the nucleus
how does ionic bonding occur
a type of bonding where one atom loses electrons and one atom gains them
it occurs between a metal and a non-metal, atoms become charged and are attracted to each other
what is covalent bonding
a type of bonding where atoms share electrons with each other
it usually occurs between non-metal atoms, diatomic molecules are formed through covalent bonding
what is metallic bonding
a type of bonding where a sea of free electrons is created
it occurs between metal atoms, electrons become delocalised and more free to move